# If we list all the natural numbers below 10 that are multiples of 3 or 5, we
# get 3, 5, 6 and 9. The sum of these multiples is 23.
# 
# Find the sum of all the multiples of 3 or 5 below 1000.

print(sum([n for n in range(1,1000) if n % 3 == 0 or n % 5 == 0]))
